The Problem of  Individuality in the Nasir al-Din Tūsi and Mulla Sadra's Approaches

Unlike the Christian philosophy، in the Islamic philosophy، the question of individuality was emerged and grew gradually in a philosophical ground. The naïve form of the problem can be found in the Farabi and Ibn Sina''s works، and its perfect form can be seen in Bahmanyar’s writings. Then، Suhrawardi considered the problem at a totally different view and separated from Peripatetics basically. After Suhrawardi، Nasir al-Din Tūsi and Mulla Sadra، were dealt with the problem، while the differences between the two philosophers’ approaches were more than their agreements. The issues related to the ‘individuality’ can be divided into four distinct debates: The conceptual bases of individuality; the affirmative principles of individuality; the Criterion of Individuality، and its justification. In the affirmative principles of individuality they are almost consentaneous، but in the other debates we can see some serious disagreements. The quiddity’s ability to justify “individuality” is the most important controversy between them. Nasir al-Din Tūsi considers quiddityas Criterion of Individuality، but Mulla Sadra belives that it is just ‘existence’ which can be the Criterion of Individuality.